There is little wiggle room on the drilling before damage occurs, if you look at the blue toroidal concentrator, the hall effect sensor chip is located on that gap.
If the drill bit got the blue toroidal loose from the potting compound, the hall effect sensor likely got damaged.
If the cart still chargers, leave it alone, but the correct prcedure would have been to use a "brass stud" and 2 short cables (1 on each side).
If the cart is not charging, as suggested, get a DPI charger from scottyb and forget about the OBC.
